Okay… Sorry about the pun, I’ll try not to do that again.
Today we are going to talk about plyometric training and how you can add it into your current workout regime to improve your explosive and maximal strength.
What Are Plyometrics?
This history of plyometric training dates back to the 1950s and was initially developed by Yuri Verkhoshansky, a Russian coach turned researcher when he began to use ‘depth jumps’ with Russian track and field jumpers. Fast forward to 1966 and Verkhoshansky had left the coaching field and began his in-depth research into what would soon be called “The Shock Method” and is now commonly referred to as plyometrics.
The Shock Method was so named due to the sharp, compulsory muscular tension, initiated by the body’s impact (collision) with an external object (i.e. The ground).
Basically, plyometrics are jumps that involve repeated, rapid, and forceful shortening and lengthening actions of major muscle groups. These shortening and lengthening actions is referred to as the stretch-shortening cycle and occurs as your muscles stretch upon impact and are followed by a concentric contraction.
Many coaches have incorporated this type of training into their athletes programs with great success improving both power and strength.
Let’s dig in…
To get a bit nerdy on you for a second…
All collisions (i.e. You stepping off a box and landing on the ground) conserve momentum, however:
- Inelastic collisions only conserve momentum
- Elastic collisions conserve momentum AND kinetic energy.
So what does that mean?
I could go into a boring explanation of this but it is just as easy for you to figure it out on your own with a simple demonstration.
So, stand up from wherever you are right now and begin to bounce up and down as you would if you were jumping rope.
You should feel the impact of the ground and the forces of your foot redirecting your energy back up into the next jump. Basically, if you are landing like EVERYONE lands when jumping rope this should feel fairly effortless and the impact should feel minimal.
This is an elastic collision and the conserved kinetic energy is “powering” the initial phase of your next jump.
Now, rock your body weight back onto your heels while continuing to jump.
I’m guessing you felt the sharp impact of your foot colliding with the ground and, to continue into the next jump, you had to provide much more effort pushing yourself up and away from the ground. Since you heel does not have elastic properties you are feeling an inelastic collision (i.e. Kinetic energy is not conserved, it is dissipated upon impact and you aren’t able to use it to power your next hop).
This is also why heel striking is no bueno (No matter how awesome your shoes are) and also why we recommend a cadence of 180 steps/minute as a minimum while running.
So, our goal when performing a jump is to maximize this elastic reaction to achieve the highest jump possible.
How do we do that?
I’m guessing you’ve seen people perform “plyometrics” in a number of way including the ever popular box jump, the vertical jump, jump squats, and possibly even depth jumps. However, some of these are more effective than the others.
As you can see in the image above the purely concentric action (Left most images) results in the lowest amount of height in a jump. However, this action is not performed very often to we’ll move on to the middle image.
The counter movement jump is incredible popular and seen throughout the research as a test of power and every day in gyms all over the world when an individual is performing a box jump. The person rapidly pulls them self down into a “launch” position, lengthening the muscles and then concentrically contracts the muscles rapidly to jump into the air or onto a box.
While the counter movement jump is quite effective, the drop jump (Far right), actually results in a faster and more powerful movement as you can see in the image below.
Now that we’ve seen a few ways we can conduct plyometrics let’s talk about the benefits of this style of training…
The Benefits of Plyometric Training
Performing plyometric training has two primary benefits:
- Miogenic – The utilization of elastic energy storage in muscle and tendon tissue
- Neurogenic – The alteration of the timing & firing rates of the motor units involved in the myotatic reflex (Stretch reflex)
So let’s unpack these two benefits a bit more…
First, the myogenic benefits basically refer to your ability to utilize the stretch-shortening cycle as efficiently as possible. Conditioning the muscles and tendons to handle the impacts and redirect that energy into something useful in the name of the game here. Plyometrics will help you achieve this which will not only make you more powerful but also protect you against injuries as you strength the muscles and tendons.
Secondly, the neurogenic benefits refer to your bodies ability to recruit motor units to power your movement. Research has shown that the inclusion of plyometric training can improve a number of EMG parameters by upwards of 20%. This means that performing plyometric training can increase you level of motor recruitment (i.e. more motor recruitment = stronger contraction = stronger you), it can increase frequency of the muscle fiber stimulated (motor unit firing rate), and improve motor unit synchronization, which is related to rate of force development.
In a study by Verkhoshansky he had a population of volleyball players perform depth jumps from a box between 50-70cm, 3 times per week for 3-5 sets of 10 reps. This routine was performed for a total of 4-weeks. After the 4-week intervention was completed the athletes were tested for explosive strength and maximal strength and it was found that both increased by 26% and 14% respectively.
So, plyometrics can improve your maximal strength and your explosive strength.
Designing a Plyometric Program
There are a number of factors to consider when beginning a plyometric program and safety is the number one priority. If you’ve ever witnessed an individual jump down from a box jump only to have his achilles tendon rupture during the landing (lengthening phase) then you know exactly what I;m talking about.
While plyometrics are a great addition to improve your maximal strength and power you must be careful that your body is prepared to handle them. Remember, if something feels sketchy, it probably is and you should stop.
With that out of the way…
Since our goal is to maximize our power output here (i.e. get more work done in less time) it makes sense to develop a program where you are using drop jumps as I’ve demonstrated above they produce the greatest amount of force in the least amount of time.
The two most effective ways I’ve seen these conducted is by either jumping down from a box and immediately jumping back up as quickly as possible or by jumping down from one box and immediately jumping up to a second box. If you have more than one box or platform to use I recommend the second so that you can control the height of both boxes to optimize your training.
How high should the box I drop off of be?
The research shows that if you are incorporating plyometric training in the hopes of improving your explosive strength and reactive ability then the box should be around .75m or ~2.5ft
If your goal is to increase maximal strength the drop height should deb around 1.1m or ~3.5ft.
I’m awesome at these, can I add weight?
You can, but it probably won’t help…
Research has shown that the addition of added body weight (via a weight vest or barbell) doesn’t increase the working effect of the take off movement. Increasing the falling weight has been shown to increase the duration of the transition — Thus, slowing you down.
So what exactly Should I do?
There is a ton of research out there with hundreds of different methods and techniques you can use to crack this nut but I like to keep things as simple as possible.
Plyometric exercises can be basically broken down into 3 categories:
- Short Coupling Time Jumping & Bounding Movements – These are characterized by very quick transition times in the stretch-shortening cycle (i.e. Quick box jumps onto a low box, jumping rope, etc)
- Long Coupling Time Jumping – These have a longer transition time such as a squat jump, or a high box jump, you may be on the ground a bit longer before you can properly redirect your energy.
- The Traditional Shock Method – Typically produce higher power outputs with the goal being increasing the height of the jump (i.e. Drop jumps)
A solid plyometric program will have a mix of these elements as each can lead to beneficial adaptations. It is also important to note that when maximal explosive strength is the goal the number of reps may be reduced while you focus on height of the jump. When you are looking to improve your transition time (reactive time) then set with higher reps can be performed.
A simple program may look like this:
- Monday – 4 x 15m – Double Leg Bounding
- Wednesday – 4 x 10 – Box Jumps (High Box)
- Friday – 4 x 5 – Drop Jumps (From a 30” box, focus on maximal jump height)
Assuming you body is not a train wreck and you can handle the impact forces and rapid lengthening and shortening of a plyometric movement without it causing injury you can start with by adding a program similar to this into you weekly workout program.
Let’s Wrap It Up
Plyometric training can be a great way to add explosive strength training to your weekly workout program and it requires very little to no equipment. With research backing up significant increases in explosive strength development & maximal strength it is an easy way to enhance your current program.
Improving your muscle and tendons ability to transfer force (rapidly) will lead to more strength and power as well as fewer injuries down the road as the tissues become conditioned to these forces.
Plyometrics may also improve rate of force development, motor unit recruitment, and muscle fiber synchronization leading to a stronger, more powerful, and overall more athletic individual which could mean all the difference when you are required to apply your fitness in your job.
(photo, Verkhoshansky, N. 2012)